1. Field of the Invention
The subject invention relates to a light emitting assembly of the type including light emitting diodes (L.E.D.s), and more particularly, light assemblies for insertion into a globe.
2. Description of the Prior Art
For over a century, municipalities have used transparent globes, such as an “Acorn” or “Type 118” luminaire to enclose and protect street light assemblies. In addition to providing protection, transparent globes are chosen over other protective covers for their appealing ornamental design. The globe is disposed around the light assembly by inserting the light assembly through a narrow opening in the bottom of the globe. Typically, in existing globes, a high-intensity discharge (H.I.D.) light bulb or a light assembly including H.I.D. lights moves into the narrow opening of the globe as the globe is moved into position to cover the light assembly. Costly reflectors or light refracting prisms are often placed around the H.I.D. lights to increase efficiency of the light assembly and direct light in a desired direction. An example of such an assembly is disclosed in U.S. Pat. No. 4,719,548 to Orosz.
Recently, municipalities desire to replace H.I.D. street light assemblies including acorn-shaped globe lamps, with L.E.D, light assemblies. L.E.D.s are more efficient than H.I.D. lights, and at least a fifty percent (50%) energy savings is possible when H.I.D. lamps are replaced with properly designed L.E.D. light assemblies. An example of such an assembly is disclosed in a PCT Application No. PCT/US2008/65874 to the inventor of the present invention, Peter Hochstein. In this Hoehstein patent application, the L.E.D.s are disposed on heat sinks including fins, and the heat sinks are appropriately spaced to effectively transfer heat away from the L.E.D.s. The expected life of such L.E.D. light assemblies can exceed 10-12 years, compared to a nominal 2-3 year life of H.I.D. lamps. An L.E.D. retrofit of standard H.I.D. street lights benefits the environment, and the L.E.D. light assemblies pay for themselves in approximately five years through the energy related cost savings.
However, existing properly designed L.E.D. light assemblies, such as the light assembly disclosed in the Hochstein patent application, do not fit through the narrow opening of the globe. L.E.D. light assemblies currently used in globes do not provide effective thermal management. Many of the prior art L.E.D. light assemblies used in globes operate at junction temperatures approaching 100 degrees Celsius, which virtually assures early degradation of the L.E.D.s. In addition to inefficient heat transfer, prior art assemblies designed to fit through the narrow opening of the globe are often inadequate because they are very small and fill only a portion of the globe, and because light from the L.E.D.s cannot be directed in a desired direction.
There remains a great need for an L.E.D. light assembly that can be inserted through the narrow opening of a globe, and also provides efficient heat transfer and directs light in a desired direction.